Phrase or idiom to mean "one at a time"

When you have too many tasks in your to-do list, you will like to clear them one at a time. Is there another way to say this? Or to say "worrying about the next one only after finishing the current one".

In my native language, we say something similar to "cut one branch at a time (of a tree)"

Doing some tasks one by one is doing them "sequentially" which is an adverb that means "in sequence".

But it sounds like you are looking for some colorful idioms. There are various in this general area, some with an exact opposite meaning.

One phrase for doing too much at once is "burning the candle at both ends", but it has some other meanings.

There is "biting off more than you can chew". I have too many tasks on my to-do list; I think I will take them one at a time and not bite off more than I can chew.

You can say, I will do this step-by-step. Or, I am moving deliberately (as opposed to precipitately).